The invention relates to a dosing device for outputting bulk goods, in particular from a storage vessel, such as a bunker or a silo.
In particular in the case of heavy-flowing bulk goods, which are subject to compressions and to the formation of bridges, measures are required for discharging the goods, which comprise the use of a discharge screw, for example. The discharge screw thereby takes over the horizontal transport of the bulk goods out of the silo or the bunker, respectively, and supplies the bulk goods conveyed in this manner to the dosing device. In the dosing device, the material flow takes place in vertical direction, wherein elements, which rotate about a vertical axis and which move the bulk goods in the direction of an output opening on the one hand and keep the bulk goods in a free-flowing manner on the other hand are used, for the most part, for preventing the slow-down of the material flow on the bottom of the dosing container. In case that the bulk goods are potentially explosive dusts, the ATEX guidelines must be considered in response to the design of the dosing vessels.
To prevent the formation of bridges of the bulk goods, from DE 10 261 395 is known the arrangement of a recessed drive front plate for a discharge screw in a dosing vessel, in which ripper teeth are additionally described at the screw blades, by means of which compressed bulk goods can be discharged better.
In the case of known dosing devices, the supply of the bulk goods out of the storage container is carried out horizontally via a conveying screw device and the discharge out of this dosing device takes place by means of actuator arms, which rotate above the container bottom. In these dosing devices, the bulk goods, which arrive from the top, are moved to the outside by means of a guide cone, which is arranged centrally about a drive shaft above the rotating discharge elements, and is supplied to the output openings via said discharge elements. A length of these discharge elements depends on the diameter of the dosing space. In the case of the long discharge elements, the speed of the dosing device required for the discharge leads to a high peripheral speed >1 m/s, whereby additional measures for explosion protection must be taken according to the ATEX guidelines in the case of dusty bulk goods, which can form an explosible atmosphere.